HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
MODX (originally MODx) is an open source content management system and web application framework for publishing content on the World Wide Web and intranets.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
PHP is a general-purpose scripting language used for web development.
Ubuntu is a free and open-source operating system on Linux for the enterprise server, desktop, cloud, and IoT.